Have I broke my teensy 4.1 board ?

kamil.szu

Member
Hi. So I was soldering pins for usb host port and I got device disconnections, so I tried to do some makeovers of those joins after that my board can't get recognized unless I press 3 times on halfkey and disable automode in this way, then board stays connected and red led is up, although after each new successful reprogramming the issue remains. Any ideas is this some strage kind of firmware issue or mechanical issue ?

Edit: its seems like I somehow broke automatic mode, because only then reprogramming fails.
 
Post a close-up picture of each side of the Teensy & maybe that will help to identify any potential problems.

Mark J Culross
KD5RXT
 
Post a close-up picture of each side of the Teensy & maybe that will help to identify any potential problems.

Mark J Culross
KD5RXT
Best what I can do with my phone
 

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I think that I just overheated some component next time I will use low temp. melting tin and set soldering tip temp at 200-230 Celsius instead of 320 even flux haven't saved this board and this one I'll use for practice.
 
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I normally solder at 400C, that way I don't need to keep iron on component for long.
Lower temp means that iron contact is for longer giving more time for heat to travel to other board components.
 
400C will char FR4 under a trace rapidly - I would never recommend running that hot for PCBs - proper temperature controlled iron is the best approach, and decently designed bits, not super thin pointy ones. Practice on scrap PCBs is a great idea - you can experiment with different temperatures that way and get your soldering time down to 2 or 3 seconds per joint.

The soldering on that header shows too much solder and a lack of flux (possibly due to rework without removing old oxidized solder first). Convex blobs of solder are always wrong, concave is correct. Use fresh solder everytime, or extra flux. Rough surface indicates a possible dry joint caused by movement whilst the solder solidifies, or a build up of oxide due to stale solder.

The hotter you run your iron the more important it is not to let it stand powered up - this leads to oxidation of the bit which makes it unwettable - to help always leave an iron well wetted with solder when in the stand, and power down if you aren't currently using it.
Clean and re-wet the bit frequently during use. Never use anything abrasive to clean a soldering bit, this will destroy the iron plating and then it will rot away in hours (copper dissolves into solder, iron does not).
 
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